1. Field of the Invention
This invention relates to a sliding surface bearing comprising a backing shell and a roll-clad sliding surface layer consisting of an aluminum alloy comprising dispersed soft interstitial elements.
2. Description of the Prior Art
Because sliding surface layers consisting of an aluminum alloy comprising dispersed soft interstitial elements cannot be roll-clad with a sufficient adhesion to a backing shell of steel, the sliding surface layer is first bonded by a rolling operation to a foil of commercially pure aluminum and that multilayer composite is then clad onto the backing shell. Whereas the interlayer consisting of the aluminum foil constitutes a suitable primer, such roll-clad bearings have a relatively low fatigue strength. This is due in the first place to the material properties of the aluminum interlayer and in the second place to the fact that the thickness of the sliding surface layer must be sufficient to provide a specified wear allowance because the aluminum interlayer does not even have emergency running properties.
To improve the fatigue strength of sliding surface bearings of the kind described first hereinbefore it would be obvious to provide an interlayer which rather than of commercially pure aluminum consists of a material having a higher strength, such as a foil of AlCu1Ni0.5. But experiments made with such foils have shown that the cold-working involved in roll-cladding results in an increase in strength and in an embrittlement of such aluminum foil, which is solid solution-hardened so that cracks are formed by which the adhesion is adversely be affected.